node.js - NodeJS - 如何在不缓冲的情况下流式传输请求正文

Question

在下面的代码中，我无法弄清楚为什么 req.pipe(res) 不起作用，但也不会引发错误。预感告诉我这是由于 nodejs 的异步行为，但这是一个非常简单的情况，没有回调。

我错过了什么？

http.createServer(function (req, res) {

  res.writeHead(200, { 'Content-Type': 'text/plain' });

  res.write('Echo service: \nUrl:  ' + req.url);
  res.write('\nHeaders:\n' + JSON.stringify(req.headers, true, 2));

  res.write('\nBody:\n'); 

  req.pipe(res); // does not work

  res.end();

}).listen(8000);

这是 curl :

➜  ldap-auth-gateway git:(master) ✗ curl -v -X POST --data "test.payload" --header "Cookie:  token=12345678" --header "Content-Type:text/plain" localhost:9002 

这是调试输出(请参阅上传的正文):

  About to connect() to localhost port 9002 (#0)
  Trying 127.0.0.1...
    connected
    Connected to localhost (127.0.0.1) port 9002 (#0)
  POST / HTTP/1.1
  User-Agent: curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8x zlib/1.2.5
  Host: localhost:9002
  Accept: */*
  Cookie:  token=12345678
  Content-Type:text/plain
  Content-Length: 243360
  Expect: 100-continue

  HTTP/1.1 100 Continue
  HTTP/1.1 200 OK
  Content-Type: text/plain
  Date: Sun, 04 Aug 2013 17:12:39 GMT
  Connection: keep-alive
  Transfer-Encoding: chunked

并且服务响应而不回显请求正文:

Echo service: 
Url:  /
Headers:
{
  "user-agent": "curl/7.24.0 (x86_64-apple-darwin12.0) libcurl/7.24.0 OpenSSL/0.9.8x zlib/1.2.5",
  "host": "localhost:9002",
  "accept": "*/*",
  "cookie": "token=12345678",
  "content-type": "text/plain",
  "content-length": "243360",
  "expect": "100-continue"
}

... 最后的 curl 调试是

Body:
 Connection #0 to host localhost left intact
 Closing connection #0

此外，当我对大型请求正文进行压力测试时，我收到 EPIPE 错误。我怎样才能避免这种情况？

-- 编辑:通过反复试验，我确实让它工作了，它仍然指向一个时间问题。虽然仍然很奇怪，因为超时会导致返回有效负载，但不介意超时持续时间。换句话说，无论我将超时设置为 5 秒还是 500 秒，有效负载都会正确地通过管道返回到请求并终止连接。

这里是编辑:

http.createServer(function (req, res) {

    try {
      res.writeHead(200, { 'Content-Type': 'text/plain' });
      res.write('Echo service: ' + req.url + '\n' + JSON.stringify(req.headers, true, 2));
      res.write('\nBody:"\n');
      req.pipe(res);
    } catch(ex) {
      console.log(ex);
      // how to change response code to error here?  since headers have already been written?
    } finally {
      setTimeout((function() {
        res.end();
      }), 500000);
    }

}).listen(TARGET_SERVER.port);

?

Answer 1

管道请求到资源。 Req 是可读流，响应是可写流。它应该可以工作

   http.createServer(function (req, res) {

       res.writeHead(200, { 'Content-Type': 'text/plain' });    
       res.write('Echo service: ' + req.url + '\n' + JSON.stringify(req.headers, true, 2));

       // pipe request body directly into the response body
       req.pipe(res);       

   }).listen(9002);